Motor vehicle exhaust pipes

ABSTRACT

A motor vehicle exhaust pipe has an end piece which is formed as a nozzle and directed downwards and is also provided with an upwardly directed bend. The upper vertex of the bend is arranged above the central axis of the exhaust pipe and the lower vertex is arranged in the region of the central axis. The cross section of the end piece is constricted in nozzle-like fashion up to the termination of the bend and is constant up to the exit aperture. This arrangement provides a rapid lead-away of the waste gases from the vicinity of the vehicle and thereby prevents soiling of the rear windows.

United States Patent Otto et a1.

[ 1 May 30, 1972 154] MOTOR VEHICLE EXHAUST PIPES [72] Inventors: Herbert Otto, Russelsheim; Helmut Schonberger, Ginsheim, both of Germany [73] Assignee: General Motors Corporation, Detroit,

Mich.

[22] Filed: Sept. 24, 1970 [21] Appl. No.: 75,047

[30] Foreign Application Priority Data Sept. 27, 1969 Germany ..P 19 48 939.5

[52] U.S. Cl. 180/64 A, 60/29 [51] Int. Cl ..B60k 13/04 [58] Field of Search 180/64 A; 181/44, 41; 138/178; 60/29 [56] References Cited UNITED STATES PATENTS 2,078,420 4/1937 Sheldrick ..60/29 R 2,674,087 4/1954 Russell ..60/32 R X FOREIGN PATENTS OR APPLICATIONS 866,150 2/1953 Germany ..180/64 A Feil, Jr. ..180/64 A Primary Examiner-William E. Wayner Attorney-J. L. Carpenter, E. J. Biskup and P. D. Sachtjen [5 7] ABSTRACT A motor vehicle exhaust pipe has an end piece which is formed as a nozzle and directed downwards and is also provided with an upwardly directed bend. The upper vertex of the bend is arranged above the central axis of the exhaust pipe and the lower vertex is arranged in the region of the central axis.

The cross section of the end piece is constricted in nozzle-like fashion up to the termination of the bend and is constant up to the exit aperture.

This arrangement provides a rapid lead-away of the waste gases from the vicinity of the vehicle and thereby prevents soiling of the rear windows.

2 Claims, 4 Drawing Figures MOTOR VEHICLE EXHAUST PIPES This invention relates to motor vehicle exhaust pipes and in particular to the end portion of a motor vehicle exhaust pipe.

It is known to form the end portion of a motor vehicle exhaust pipe with a downward inclination to the horizontal with the intention of directing the exhaust gases rapidly away from the vicinity of the'vehicle by providing the end portion with a downward inclination and a downwardly inclined and is of nozzle formation. This construction does not, however, result in the desired concentration of the jet of exhaust gases nor does it bring about a substantially better dissipation of the exhaust gases than does a straight horizontally directed end portion of an exhaust pipe.

it is also known to make the end portion of the exhaust pipe with an outlet opening the cross section of which is substantially decreased relative to the cross section of the main portion of the pipe and to bend the end portion upwardly and taper it so that it is reduced from a circular cross section to a narrow elongated slot, the major axis of which is parallel with the road. With this construction the exhaust gases are dispersed laterally by the slot-like outlet opening to form a ribbon shaped jet but this construction has the disadvantage that, because of the small exit aperture, the performance of the engine is considerably reduced.

It is also well known to conduct the exhaust gases away from the vehicle through a horizontally directed end portion of an exhaust pipe and to use an arrangement of dual exhaust pipes located one to each side of the rear end of the vehicle, but such an arrangement does not result in a rapid conduction of the exhaust gases away from the vicinity of the vehicle.

In a motor vehicle exhaust pipe according to the invention, the end portion of the exhaust pipe has an upwardly directed bend.

The upper wall of the pipe, at the vertex of the bend is arranged above the central axis of the exhaust pipe and the lower wall at the vertex is arranged in the region of the central longitudinal axis of the exhaust pipe.

The end portion is so designed that it is constricted in nozzle-like fashion in the region of the bend and has a constant cross section from the termination of the bend up to the outlet opening. This arrangement ensures that the exhaust gas is accelerated in the region of the bend and at the same time it is directed downwards with respect to the horizontal so that it emerges from the outlet opening with increased velocity.

The cross section of the outlet opening of the end portion is of elongated shape with its major axis lying parallel with the road.

The cross-sectional area of the exit aperture is about 75 percent of that of the cross section of the exhaust pipe.

Moreover, the portion of the end piece formed with a constant cross section is directed downwards at an angle of about 35.

The end portion is provided with a cover pipe whose opening terminates flush with the outlet opening of the end portion or projects only slightly beyond it; the opening of the cover pipe is in a plane parallel to the plane of the outlet opening of the end portion.

The scope of the invention is defined by the appended claims; and the invention and the method by which it is to be performed are hereinafter particularly described with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of the rear end of a motor vehicle with dual exhaust pipes the end portions of which are provided with cover pipes;

FIG. 2 is a side elevation of the end portion of one of the exhaust pipes;

FIG. 3 is an end elevation of the end portion of the exhaust pipe of FIG. 2, as viewed in the direction of the arrow A; and

FIG. 4 is a part sectional side elevation of the end portion of the exhaust pipe, the cover pipe being shown partially broken away.

Figure 1 shows the rear end 10 of a motor vehicle having a-bumper 11 with an over-rider 12, a housing 13 for a light for a number plate 14, and rear lights 15. Protruding below the body 16 of the vehicle are the two end portions 21 (Figures 2 and 4) of a pair of exhaust pipes 17, the end portions 21 having outlet openings 18 and cover pipes 19. As shown on Figures 2 and 4 each exhaust pipe 17 has an end resonator silencer 20 which continues into the end portion 21 which has an upwardly directed bend 22 therein, the bend 22 having at its vertex an upper wall 23 which lies above and is spaced from the central longitudinal axis 24 of the exhaust pipe 17, and having a lower wall 25 which lies adjacent the longitudinal axis 24. The bent portion 22 of the exhaust pipe continues into a downwardly inclined portion 26 which terminates in the outlet opening 18, the portion 26 of the pipe extending at an angle of approximately 35 to the longitudinal axis 24. The end portion 21 of the exhaust pipe tapers, as shown, towards its junction with the bend 22 therein but the downwardly inclined portion 26 is of substantially constant cross-section. As shown in Figure 3, the outlet 18 of the exhaust pipe is of substantially elliptical form, with the major axis thereof extending transversely, that is, parallel to the road, and with the upper wall of the outlet 18 intersecting the longitudinal axis 24.

As shown in Figure 4, the cover pipe 19 which encloses the silencer 20 and end portion 21 of the exhaust pipe has an end opening 28 the plane of which is preferably substantially parallel to the downwardly inclined plane of the outlet opening 18 of the end portion 21; and the plane of the outlet opening 18 is preferably spaced slightly inwardly of the outlet 28 by chstance of approximately 2 millimeters. WA

The cover pipe 19 ensures that the flow of exhaust gases is not broken oftat the outlet opening 18 of the end portion 21 of the exhaust pipe and that the flow of exhaust gases is conducted away, substantially undisturbed, in the wind shadow" of the cover pipe 19.

Preferably the cross-sectional area of the outlet opening 18 is approximately 75 percent of that of the exhaust pipe.

The exhaust gases are accelerated as they pass through the region of the bend 22 of the end portion 21 of the exhaust pipe 17 and at the same time the gases are directed downwardly at an angle to the horizontal.

The elongated form of the outlet opening 18 creates a ribbon shaped jet of exhaust gases, and the ratio between the cross-sectional area of the outlet opening 18 to that of the exhaust pipe ensures that there is only a slight obstruction to flow through the pipe and correspondingly only a slight reduction in the efiective power of the engine. The selection of an angle of approximately 35 for the downwardly inclined portion 26 of the exhaust pipe assists in preventing the exhaust gases from passing into the negative pressure region rearwardly of the vehicle, the exhaust gases being directed under the tail vortex of the vehicle and thus being rapidly removed from the vicinity of the vehicle.

We claim:

1. In a motor vehicle, the combination comprising: an exhaust pipe having a longitudinal axis, said exhaust pipe adapted to be connected to the vehicle with said longitudinal axis extending substantially horizontally; an end piece on the exhaust pipe; an upwardly directed bend in a front section of said end piece having a gradually decreasing cross sectional area, said bend having an upper vertex arranged above said longitudinal axis and a lower vertex arranged in the vicinity of said longitudinal axis; and a terminal end of substantially constant cross-sectional area on a rear section of said end piece extending downwardly and rearwardly of said upper vertex and said lower vertex, said terminal end having a discharge opening below said longitudinal axis whereby the configuration and disposition of said bend and said terminal end direct exhaust gases flowing through the exhaust pipe under the tail vortex of the vehicle.

2. In a motor vehicle, the combination comprising: a cylindrical exhaust pipe through which exhaust gases flow, said exhaust pipe adapted to be connected to the vehicle with a lonsaid exhaust pipe, said terminal end extending downwardly and rearwardly from said walls to said discharge opening, said terminal end terminating below said longitudinal axis whereby the configuration and disposition of said nozzle and said terminal end are effective to direct said exhaust gases under the tail vortex developed when the vehicle is moving; and a cover pipe encircling said end piece and terminating substantially adjacent said discharge opening for providing a protective covering for the end piece.

OI i I I I. 

1. In a motor vehicle, the combination comprising: an exhaust pipe having a longitudinal axis, said exhaust pipe adapted to be connected to the vehicle with said longitudinal axis extending substantially horizontally; an end piece on the exhaust pipe; an upwardly directed bend in a front section of said end piece having a gradually decreasing cross sectional area, said bend having an upper vertex arranged above said longitudinal axis and a lower vertex arranged in the vicinity of said longitudinal axis; and a terminal end of substantially constant crosssectional area on a rear section of said end piece extending downwardly and rearwardly of said upper vertex and said lower vertex, said terminal end having a discharge opening below said longitudinal axis whereby the configuration and disposition of said bend and said terminal end direct exhaust gases flowing through the exhaust pipe under the tail vortex of the vehicle.
 2. In a motor vehicle, the combination comprising: a cylindrical exhaust pipe through which exhaust gases flow, said exhaust pipe adapted to be connected to the vehicle with a longitudinal axis thereof extending horizontally of the vehicle; an end piece having a discharge opening for said exhaust gases; a bend in said end piece extending upwardly and rearwardly of the vehicle, said bend having an upper wall and a lower wall defining a constricted nozzle having a gradually decreasing cross-sectional area, said upper wall having a vertex disposed above said longitudinal axis, and said lower wall having a vertex arranged in the vicinity of said longitudinal axis; a transversely elongated terminal end having surfaces defining a substantially constant cross-sectional area on a rear section of said exhaust pipe, said terminal end extending downwardly and rearwardly from said walls to said discharge opening, said terminal end terminating below said longitudinal axis whereby the configuration and disposition of said nozzle and said terminal end are effective to direct said exhaust gases under the tail vortex developed when the vehicle is moving; and a cover pipe encircling said end piece and terminating substantially adjacent said discharge opening for providing a protective covering for the end piece. 